Modified polyimide compound, resin composition and polyimide film

ABSTRACT

A resin composition comprises a modified polyimide compound, an epoxy resin, and a solvent. The modified polyimide compound has a chemical structural formula of 
                         
the Ar′ represents a group selected from a group consisting of phenyl having a chemical structural formula of
 
                         
diphenyl ether having a chemical structural formula of
 
                         
biphenyl having a chemical structural formula of
 
                         
hexafluoro-2,2-diphenylpropane having a chemical structural formula of
 
                         
benzophenone having a chemical structural formula of
 
                         
and diphenyl sulfone having a chemical structural formula of
 
                         
and any combination thereof, the modified polyimide compound has a degree of polymerization n of about 1 to about 50, the epoxy resin and the modified polyimide compound are in a molar ratio of about 0.1:1 to about 1:1. A modified polyimide compound and a polyimide film are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of patent application Ser. No.15/689,166, filed on, Aug. 29, 2017, assigned to the same assignee,which is based on and claims priority to Taiwan Patent Application No.106101438 filed on Jan. 16, 2017, the contents of which are incorporatedby reference herein.

FIELD

The subject matter herein generally relates to a modified polyimidecompound, a resin composition, and a polyimide film.

BACKGROUND

Flexible circuit boards usually include polyimide films. Such polyimidefilm is formed by diamine compounds and anhydride compounds, and has ahigh dielectric constant D_(k) (greater than 3.0). Thus, the flexiblecircuit board cannot provide an impedance match for high frequencysignals to be transmitted thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present technology will now be described, by wayof example only, with reference to the attached figures.

FIG. 1 is a flowchart of an exemplary embodiment of a method formanufacturing a polyimide film.

FIG. 2 is a diagram of an exemplary embodiment of a circuit board.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration,where appropriate, reference numerals have been repeated among thedifferent figures to indicate corresponding or analogous elements. Inaddition, numerous specific details are set forth in order to provide athorough understanding of the embodiments described herein. However, itwill be understood by those of ordinary skill in the art that theembodiments described herein can be practiced without these specificdetails. In other instances, methods, procedures, and components havenot been described in detail so as not to obscure the related relevantfeature being described. Also, the description is not to be consideredas limiting the scope of the embodiments described herein. The drawingsare not necessarily to scale, and the proportions of certain parts maybe exaggerated to better illustrate details and features of the presentdisclosure.

The term “comprising,” when utilized, means “including, but notnecessarily limited to”; it specifically indicates open-ended inclusionor membership in the so-described combination, group, series, and thelike.

An exemplary embodiment of a resin composition comprises a modifiedpolyimide compound, an epoxy resin, and a solvent. In at least oneexemplary embodiment, the epoxy resin and the modified polyimidecompound are in a molar ratio of about 0.1:1 to about 1:1.

The modified polyimide compound has a chemical structural formula of

wherein Ar′ represents a group selected from a group consisting ofphenyl having a chemical structural formula of

diphenyl ether having a chemical structural formula of

biphenyl having a chemical structural formula of

hexafluoro-2,2-diphenylpropane having a chemical structural formula of

benzophenone having a chemical structural formula of

and diphenyl sulfone having a chemical structural formula of

and any combination thereof. In at least one exemplary embodiment, themodified polyimide compound has a degree of polymerization of about 1 toabout 50.

In at least one exemplary embodiment, the modified polyimide compound ismade by the following steps:

The epoxy resin has a chemical structure selected from a groupconsisting of

and any combination thereof.

In at least one exemplary embodiment, the solvent isN,N-dimethylacetamide.

In at least one exemplary embodiment, the resin composition can furthercomprise of porous materials. In this exemplary embodiment, the porousmaterials are molecular sieves obtainable from Tianjin Nankai UniversityCatalyst Plant under the trade name “MCM-41”. The modified polyimidecompound and the porous materials are in a ratio of about 1000:1 toabout 10:1 by weight.

A method for preparing the resin composition may comprise the followingsteps: (1) adding the modified polyimide compound, the epoxy resin, andthe solvent in a vessel; (2) stirring the modified polyimide compound,the epoxy resin, and the solvent until the modified polyimide compoundand the epoxy resin dissolve in the solvent.

FIG. 1 illustrates a flowchart of a method for manufacturing a polyimidefilm 20 (shown in FIG. 2) using the resin composition in accordance withan exemplary embodiment. The exemplary method is provided by way ofexample, as there are a variety of ways to carry out the method. Eachblock shown in the figure represents one or more processes, methods, orsubroutines, carried out in the exemplary method. Furthermore, theillustrated order of blocks is by example only, and the order of theblocks can change. Additional blocks may be added, or fewer blocks maybe utilized, without departing from this disclosure. The exemplarymethod can begin at block 11.

At block 11, the resin composition is coated on a surface of a base, andis heated to cause the modified polyimide compound and the epoxy resinto undergo a polymerization reaction. In at least one exemplaryembodiment, the resin composition is placed in a furnace and heatedthrough four heating processes. The first heating process is heating theresin composition from 25 degrees Celsius to 140 degrees Celsius andmaintaining the heating of the resin composition at 140 degrees Celsiusfor 30 min. The second heating process is heating the resin compositionfrom 140 degrees Celsius to 180 degrees Celsius and maintaining theheating of the resin composition at 180 degrees Celsius for 2 hours. Thethird heating process is heating the resin composition from 180 degreesCelsius to 200 degrees Celsius and maintaining the heating of the resincomposition at 200 degrees Celsius for 2 hours. The fourth heatingprocess is heating the resin composition from 200 degrees Celsius to 220degrees Celsius and maintaining the heating of the resin composition at220 degrees Celsius for 2 hours.

At block 12, after the polymerization reaction, the resin composition isdried and separated from the base, thereby forming the polyimide film20.

FIG. 2 illustrates an exemplary embodiment of a circuit board 100comprising at least one circuit substrate 30 and a polyimide film 20formed on at least one surface of each circuit substrate 30. Thepolyimide film 20 is formed by heating the resin composition, to causethe modified polyimide compound and the epoxy resin of the resincomposition to undergo a polymerization reaction.

In the resin composition, the modified polyimide compound comprisesacrylate groups at side chains. When the resin composition is heated toform the polyimide film 20, the acrylate groups at side chains of themodified polyimide compound and the epoxy resin react with each other,to reduce a dielectric constant D_(k) of the polyimide film 20.Furthermore, the resin composition can form a cross-linking structurewhen the resin composition is heated to form the polyimide film 20,which can increase the cross-linking density of the polyimide film 20,so that heat resistance of the polyimide film 20 is improved forsoldering. Thus, the polyimide film 20 can have an improved thermalresistance. Moreover, because the modified polyimide compound comprisesof 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide groups, thepolyimide film 20 has a preferred flame retardancy. In addition, whenthe resin composition is comprised of porous materials, air canpenetrate the porous materials of the polyimide film 20 to furtherdecrease the dielectric constant D_(k).

Example 1

4.8 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 3.0g of 4-aminoacetophenone of, 4.8 g of 2-aminophenol, 0.19 g of4-methylbenzenesulfonic acid (P-TSA), and 10.0 g of dimethyl sulfoxidewere added into a first container and stirred. The first container washeated at 100 degrees Celsius for 12 hours under a nitrogen atmosphereto form a first product having a chemical structural formula of

1.0 g of the first product, 0.7 g of 1,2,4,5-benzenetetracarboxylicanhydride, 6.8 g 1-methyl-2-pyrrolidinone (NMP), and 3.4 g xylene wereadded into a second container and stirred. The second container washeated at 140 degrees Celsius for 20 hours under a nitrogen atmosphereto initiate a reflux reaction to form a second product having a chemicalstructural formula of

10.0 g of the second product, 3.5 g of methacrylic anhydride, 0.1 g ofsodium acetate, and 100.0 g of N,N-dimethylacetamide (DMAC) were added athird container and stirred. The third container was heated at 80degrees Celsius for 12 hours under a nitrogen atmosphere to initiate areflux reaction to form a modified polyimide compound (I) having achemical structural formula of

100.0 g of the modified polyimide compound (I), an epoxy resin having achemical structural formula of

and 100.0 g of N,N-dimethylacetamide were added into a fourth containerand stirred to form the resin composition. The epoxy resin and themodified polyimide compound (I) were in a molar ratio of 1:1. The resincomposition had a viscosity of about 50000 cps.

Example 2

Modified polyimide compound (II) having a chemical structural formula of

was formed. Different from the example 1, 0.7 g of the1,2,4,5-benzenetetracarboxylic anhydride was replaced by 0.7 g of4,4′-oxydiphthalic anhydride.

100.0 g of the modified polyimide compound (II), an epoxy resin having achemical structural formula of

and 100.0 g of N,N-dimethylacetamide were added into a container andstirred to form the resin composition. The epoxy resin and the modifiedpolyimide compound (II) were in a molar ratio of 1:1. The resincomposition had a viscosity of about 40000 cps.

Example 3

Modified polyimide compound (III) having a chemical structural formulaof

was formed. Different from the example 1, 0.7 g of the1,2,4,5-benzenetetracarboxylic anhydride was replaced by 0.7 g of3,4,3′,4′-biphenyltetracarboxylic dianhydride.

100.0 g of the modified polyimide compound (III), an epoxy resin havinga chemical structural formula of

and 100.0 g of N,N-dimethylacetamide were added into a container andstirred to form the resin composition. The epoxy resin and the modifiedpolyimide compound (III) were in a molar ratio of 1:1. The resincomposition had a viscosity of about 48000 cps.

Example 4

Modified polyimide compound (IV) having a chemical structural formula of

was formed. Different from the example 1, 0.7 g of the1,2,4,5-benzenetetracarboxylic anhydride was replaced by 0.7 g of4,4′-(hexafluoroisopropylidene)diphthalic anhydride.

100.0 g of the modified polyimide compound (IV), an epoxy resin having achemical structural formula of

and 100.0 g of N,N-dimethylacetamide were added into a container andstirred to form the resin composition. The epoxy resin and the modifiedpolyimide compound (IV) were in a molar ratio of 1:1. The resincomposition had a viscosity of about 23000 cps.

Example 5

Modified polyimide compound (V) having a chemical structural formula of

was formed. Different from the example 1, 0.7 g of the1,2,4,5-benzenetetracarboxylic anhydride was replaced by 0.7 g of3,3′,4,4′-benzophenonetetracarboxylic dianhydride.

100.0 g of the modified polyimide compound (V), an epoxy resin having achemical structural formula of

and 100.0 g of N,N-dimethylacetamide were added into a container andstirred to form the resin composition. The epoxy resin and the modifiedpolyimide compound (V) were in a molar ratio of 1:1. The resincomposition had a viscosity of about 50000 cps.

Example 6

Modified polyimide compound (VI) having a chemical structural formula of

was formed. Different from the example 1, 0.7 g of the1,2,4,5-benzenetetracarboxylic anhydride was replaced by 0.7 g of3,3′,4,4′-diphenyl sulfonetetracarboxylic anhydride.

100.0 g of the modified polyimide compound (VI), an epoxy resin having achemical structural formula of

and 100.0 g of N,N-dimethylacetamide were added into a container andstirred to form the resin composition. The epoxy resin and the modifiedpolyimide compound (VI) were in a molar ratio of 1:1. The resincomposition had a viscosity of about 40000 cps.

Example 7

100.0 g of the modified polyimide compound (III) of example 3, 0.5 g ofmolecular sieves (Manufacturer: Tianjin Nankai University CatalystPlant, Model: “MCM-41”), and an epoxy resin having a chemical structuralformula of

and 100.0 g of N,N-dimethylacetamide were added into a container andstirred to form the resin composition. The epoxy resin and the modifiedpolyimide compound (III) were in a molar ratio of 1:1. The resincomposition had a viscosity of about 48000 cps.

Comparative Example 1

70 g of 1,4-benzenediamine, 30 g of 3,4,3′,4′-biphenyltetracarboxylicdianhydride, and 100 g of N,N-dimethylacetamide were added into acontainer and stirred to form a resin composition. The resin compositionhad a viscosity of about 40000 cps.

Comparative Example 2

70 g of 1,4-benzenediamine, 30 g of a modified3,4,3′,4′-biphenyltetracarboxylic dianhydride which was modified bymethacrylic anhydride, and 100 g of N,N-dimethylacetamide were addedinto a container and stirred to form a resin composition. The resincomposition had a viscosity of about 20561 cps.

Comparative Example 3

70 g of 1,4-benzenediamine, 30 g of 3,4,3′,4′-biphenyltetracarboxylicdianhydride, 0.5 g of molecular sieves (Manufacturer: Tianjin NankaiUniversity Catalyst Plant, Model: “MCM-41”), and 100 g ofN,N-dimethylacetamide were added into a container and stirred to form aresin composition. The resin composition had a viscosity of about 25656cps.

Seven first test samples were made. Each of the seven first test samplescomprises a copper foil and a polyimide film made by heating the resincompositions of the examples 1, 2, 3, 4, 5, 6, and 7, respectively,through four heating processes. The first heating process is heating theresin composition from 25 degrees Celsius to 140 degrees Celsius andmaintaining the heating of the resin composition at 140 degrees Celsiusfor 30 min. The second heating process is heating the resin compositionfrom 140 degrees Celsius to 180 degrees Celsius and maintaining theheating of the resin composition at 180 degrees Celsius for 2 hours. Thethird heating process is heating the resin composition from 180 degreesCelsius to 200 degrees Celsius and maintaining the heating of the resincomposition at 200 degrees Celsius for 2 hours. The fourth heatingprocess is heating the resin composition from 200 degrees Celsius to 220degrees Celsius and maintaining the heating of the resin composition at220 degrees Celsius for 2 hours.

Three second test samples were made. Each of the three second testsamples comprises a copper foil and a polyimide film made by heating theresin compositions of the comparative examples 1, 2, and 3,respectively, through two heating processes. The first heating processis heating the resin composition from 25 degrees Celsius to 140 degreesCelsius and maintaining the heating of the resin composition at 140degrees Celsius for 30 min. The second heating process is heating theresin composition from 140 degrees Celsius to 350 degrees Celsius andmaintaining the heating of the resin composition at 350 degrees Celsiusfor 1 hours.

Dielectric constant D_(k), and dielectric dissipation factor D_(f) ofeach of the polyimide films formed by the resin compositions of examples1 to 7 and the resin compositions of the comparative examples 1 to 3were tested. Thermal resistance, and copper peeling strength of theseven first test samples and the three second test samples were tested.The test results were shown in the following Table 1. The thermalresistance was tested at a temperature of 288 degrees centigrade for 10seconds, if the polyimide film did not blister and peel off, the resultof the thermal resistance test is considered passing, otherwise, theresult fails.

TABLE 1 Product Example Example Example Example Example Example ExampleComparative Compamtive Comparative Property 1 2 3 4 5 6 7 example 1example 2 example 3 D_(k) (10 GHz) 2.75 2.90 2.83 2.55 2.82 2.95 2.903.20 3.10 3.00 D_(f) (10 GHz) 0.008 0.009 0.006 0.006 0.008 0.009 0.0060.006 0.011 0.005 Results of the Pass Pass Pass Pass Pass Pass Pass PassPass Pass thermal resistance test Copper peeling 0.96 0.93 0.97 0.960.96 0.93 0.97 1.02 1.04 0.98 strength (kgf/cm)

According to the Table 1, the dielectric constant of the polyimide filmsformed by the resin compositions of examples 1, 2, 3, 4, 5, 6, and 7 arelower than the polyimide films formed by the resin compositions of thecomparative examples 1, 2, and 3. In addition, the polyimide films madeby the resin compositions of the examples 1, 2, 3, 4, 5, 6, and 7 have apreferred thermal resistance, respectively.

It is to be understood, even though information and advantages of thepresent embodiments have been set forth in the foregoing description,together with details of the structures and functions of the presentembodiments, the disclosure is illustrative only; changes may be made indetail, especially in matters of shape, size, and arrangement of partswithin the principles of the present embodiments to the full extentindicated by the plain meaning of the terms in which the appended claimsare expressed.

What is claimed is:
 1. A resin composition comprising: a modifiedpolyimide compound; an epoxy resin; and a solvent; wherein the modifiedpolyimide compound has a chemical structural formula of

the Ar′ represents a group selected from a group consisting of phenylhaving a chemical structural formula of

diphenyl ether having a chemical structural formula of

biphenyl having a chemical structural formula of

hexafluoro-2,2-diphenylpropane having a chemical structural formula of

benzophenone having a chemical structural formula of

and diphenyl sulfone having a chemical structural formula of

and any combination thereof, the modified polyimide compound has adegree of polymerization n of 2 to 50, the epoxy resin and the modifiedpolyimide compound are in a molar ratio of about 0.1:1 to about 1:1. 2.The resin composition of claim 1, wherein the resin composition furthercomprises porous materials.
 3. The resin composition of claim 2, whereinthe modified polyimide compound and the porous materials are in a ratioof about 1000:1 to about 10:1 by weight.
 4. The resin composition ofclaim 1, wherein the solvent is N,N-dimethylacetamide.
 5. A polyimidefilm formed by heating a resin composition to undergo a polymerizationreaction, wherein the resin composition comprises a modified polyimidecompound, an epoxy resin, and a solvent, the modified polyimide compoundand the epoxy resin are heated to undergo the polymerization reaction,the modified polyimide compound has a chemical structural formula of

the Ar′ represents a group selected from a group consisting of phenylhaving a chemical structural formula of

diphenyl ether having a chemical structural formula of

biphenyl having a chemical structural formula of

hexafluoro-2,2-diphenylpropane having a chemical structural formula of

benzophenone having a chemical structural formula of

and diphenyl sulfone having a chemical structural formula of

and any combination thereof, the modified polyimide compound has adegree of polymerization n of 2 to 50, the epoxy resin and the modifiedpolyimide compound are in a molar ratio of about 0.1:1 to about 1:1. 6.The polyimide film of claim 5, wherein the resin composition furthercomprises porous materials.
 7. The polyimide film of claim 6, whereinthe modified polyimide compound and the porous materials are in a ratioof about 1000:1 to about 10:1 by weight.
 8. The polyimide film of claim5, wherein the solvent is N,N-dimethylacetamide.
 9. A modified polyimidecompound having a chemical structural formula of

wherein the Ar′ represents a group selected from a group consisting ofphenyl having a chemical structural formula of

diphenyl ether having a chemical structural formula of

biphenyl having a chemical structural formula of

hexafluoro-2,2-diphenylpropane having a chemical structural formula of

benzophenone having a chemical structural formula of

and diphenyl sulfone having a chemical structural formula of

and any combination thereof, the modified polyimide compound has adegree of polymerization n of 2 to 50.